Hierarchical Carbon Materials Derived From Biomass For Adsorptional And Electrochemical Performance

Hierarchical porous carbon materials have been widely applied due to good electrical conductivity,strong skeleton rigidity,and large specific surface area.Therefore,they have been used in many fields,such as adsorbents,fuel cells,super capacitors,and catalyst carriers.Employing biomass as carbon precursor to prepare hierarchical porous carbon materials is of great significance for reducing waste and reducing costs.In this work,three different biomass was used to prepare hierarchical porous carbon powder?HPC?,carbon monoliths?WCM?,and carbon fiber aerogels?N-CFA?.The CO₂ adsorption or electrochemical performance of those hierarchical porous carbon materials are investigated.1)Waste chrysanthemum tea was used as carbon precursor to preapre porous carbons with good adsorbability for CO2.N2 adsorption-desorption analysis suggested that both the ZnCl₂/chrysanthemum ratio and carbonization temperature are critical for the formation of specific surface area and porous structure,which are the key factors for CO₂adsorption.2)The WCM material derived from wax gourd as highly hydrated and natural carbon precursors could be used as efficient all-carbon electrode for symmetric supercapacitor application.The synthesis strategy combining freeze drying and direct carbonization without any chemical or physical activation enabled the as-prepared WCM to feature with highly hierarchal porosity,large specific surface area and excellent mechanical strength.Employing WCM as all-carbon electrodes in supercapacitor,it displays a high specific capacitance and a remarkable stability.3)The raw cotton was employed as a fibrous template to fabricate shaped aerogels and ZIF-8 was in situ fabricated on the surface of cotton to create rich porous structure and nitrogen doping.The obtained N-CFA exhibited macro monolith morphology,highly elastic properties and good flexibility inherited from raw cotton.The introduction of ZIF-8endowed the as-prepared N-CFA with high surface area,rich porous structure and nitrogen doping.As a binder free electrode,the N-CFA showed remarkable capacity and excellent rate capability.